Congratulations on an exceptional additition to your remarkable collection. I Couldn't agree more, the Ref 666A (no date) is IMHO the perfectest Ingenieur.The interesting thing about this model is that the dial is not made of soft iron. The Faraday cage is completed by a soft iron disk between the movement and the dial. The dials have longer feet to account for the loger distance so they can be securely attached to the movement.I am still looking for the Ref 866A.

clepsydra Wrote:Congratulations on an exceptional additition to your remarkable collection. I Couldn't agree more, the Ref 666A (no date) is IMHO the perfectest Ingenieur.The interesting thing about this model is that the dial is not made of soft iron. The Faraday cage is completed by a soft iron disk between the movement and the dial. The dials have longer feet to account for the loger distance so they can be securely attached to the movement.I am still looking for the Ref 866A.

And thanks, water clock, for the interesting factoid about the soft iron encapsulation. Is it true for all 666's without date?

Hi MichaelI got this information directly from Schaffhausen a couple of years ago, I can't recall from whom. I was attempting to determine the authenticity of a Ref 666A (no date) dial because it was not attracted by a magnet and got that information. I assumed it applied to all Ref 666A.

Heiko,Another great post with excellent photography. Indeed few of the vintage Ingenieurs were manufactured without date. Another example among those you mention, is the Ref. 766, the golden Ingenieur with steel case back.Kind regards,Adrian,(alwaysiwc).